However, Timothy Henrich -- from the division of infectious diseases at Brigham -- said not to celebrate a cure quite yet. While the virus isn't detectable in blood or tissue, it could be hiding in other places like organs and reappear later.

Even if the virus doesn't reappear, bone marrow transplants are not something to be taken lightly. There is a 15-20 percent mortality rate and patients must take immunosuppressive drugs for the rest of their lives (which prevent the immune system from performing normal duties, such as fighting off infections).

"While these results are exciting, they do not yet indicate that the men have been cured," said Henrich. "Long-term follow up of at least one year will be required to understand the full impact of a bone marow transplant on HIV persistence."

Nevertheless, this is a great finding that could lead to a better understanding of the virus, better treatments and eventually (hopefully) a cure.

"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." -- Bill Gates